Glass fusion is a fun and simple process of melting sheets of glass together, either in stacked form with a little heat or flattened together into one solid piece when more heat is applied. The result is a beautiful and innovative piece of jewelry. A great starter kit, 90 COE glass can be melted in a home microwave using the included kiln. In addition to the kiln, the kit also includes pendant, earring and bracelet findings, glass sheets, millefiori glass, confetti glass and metallic patterned glass, along with hot mitts, glass cutter, kiln paper and complete instructions. Kiln is 5-1/4 x 5-1/4 inches overall with an inside diameter of 3-1/4 x 3-1/4 inches. Cracks on inside of kiln are expected as a result of regular use.